4. Let A = 1 a) T(u), T(v), and T(u - 2v). and T: R² → R2 by T(X) = AX. Find b) Find the vector X whose image by T is b = [], i. e. T(X) = b.

Consider the vector v=(1,3,0,4). Find u such that a u has the same direction as v and one-half of its length. b u has the direction opposite that of v and twice its length.